Space heating apparatus



United States Patent [54] SPACE HEATING APPARATUS 9 Claims, 3 DrawingFigs.

[52] U.S. Cl. 263/19, 126/1 10 [51 1 int. Cl F231 9/04 [50] FieldofSearch 263/19;

[56] References Cited UNITED STATES PATENTS 8/1953 Heiman 126/1103,270,738 9/1966 Nielsen 126/110 FUREIGN PATENTS 219,136 12/1958Australia 126/110 717,859 2/1942 Germany 126/110 Primary Examiner-Edward G. Favors Attorney-Harness, Dickey & Pierce ABSTRACT: Apparatusfor heating the space within a building consists of a sheet metalcabinet supported by the roof and projecting downwardly through anopening in the roof as well as upwardly above the roof and defining ahooded inlet for fresh air. The unit contains a burner above the roof, acentrifugal fan on a vertical axis below the roof and depending frorrthe ceiling into the building. Fresh air is drawn from above the roofinto the top of the cabinet, downwardly through a burnel containedtherein and laterally in all directions within the in terior of thebuilding space.

Patented Nov. 24, 197% 3,542,373

Sheet 2 012 l SPACE HEATING APPARATUS BACKGROUND OF THE INVENTIONSo-c'alled makeup air heaters of a direct fired type in common useconsist ofa cabinet adapted to be mounted outside a building, frequentlyupon the roof, and containing an open flame gas burner and a centrifugalfan, fresh air being drawn through the burner and projected into thebuilding. In addition to the cabinet structure required in suchassemblies as presently in general use, it'has also been considerednecessary to enclose the centrifugal fan in ahousing of the scroll type,and to provide within the building deflecting means for distributing theoutlet air in desired directions and to eliminate the direct blast fromthe fan which would otherwise conccn Irate the output in a singledirection. The present invention improves upon the aforementioned commontype of roofmounted makeup airheater in several respects, while at thesame time provides a'more compact, more attractive, quieter constructionand one which is less costly both to manufacture and to install. Theinvention requires no special fan casing, no special air distributingmeans, and distributes the output throughout 360.

The objects ofthe invention may be summarized as directed to theimprovement of such heaters in the indicated respects, and furtherobjects and advantages will become apparent upon consideration of thepresent disclosure in its entirety.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING FIG. I is a verticalcross-sectional-view of a heater constructed in accordance with thepresent invention, showing the same installed in a roof which isfragmentarily diagrammatically illustrated;

FIG. 2 is a horizontal sectional plan view taken substantially on theline 11-" of FIG. I, looking in the direction of the arrows; and

FIG. 3 is a vertical section taken substantially on the line III-III ofFIG. I and looking in the direction of the arrows.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to thedrawing, reference character designates generally a roof structurethe-details of which may vary and in themselves form no part of mypresent invention, but which is provided with a rectangular opening 12and suitable flashing 14, which provides a weather seal to a stepped orZ-section metallic supporting frame 15 extending around the opening 12,mounted on supporting curbing 16 which extends around the opening. Frame15 is contoured to provide a horizontal supporting shelf flange 18 nearor somewhat below the roof top plane and upon which rests the cabinetstructure generally designated 20. The rectangular Sheet metal cabinetstructure extends upwardly above the roof and carries at its top a sheetmetal weather hood 22 which extends outwardly on all sides around thevertical cabinet walls and has turneddown weather protective sidesdefining inlet openings 24 on all four sides through which air enters inan upward direction. The vertical walls open into the hood so that theair must flow inwardly and turn 180 to then flow downwardly through thecabinet and through the framed opening into the building. Filters 25 ofconventional or any suitable type are provided in the openings 24,removably mounted in channel frames 26 so that they may be installed,removed and serviced through the openings 24.

The cabinet also supports, in a position projecting upwardly into thehood 22 an open-flame-type gas burner 30, although other sources of heatmay of course be used. The entrance to the cabinet may be somewhatrestricted, depending upon the desired type and capacity ofthe heatsource, by a top panel 32 containing an inlet opening 33 proportioned tothe particular burner which the designer may install, as desiredcapacity and other engineering considerations may dictate.

A fan support'fr grg egstructure is secured to the main frame 18 anddepends info -th building space, consisting of vertical framing members35 attached at their upper ends to frame I8 and carrying at their lowerends transverse horizontal framing members 36 and a bottom closure panel44. The cabinet structure 20 also carries in a position spaced above theroof line horizontal cross frame members 38. The vertical dependingframing members 35 are positioned to surround and support a circular fanarea within which a centrifugal fan impeller 40 is mounted to rotate ona vertical axis in bearings 41, 42 carried by cross members 3o, 38.Panel 44 blocks the lower side ofthe impeller and prevents directdownflow of incoming air. The cagelike enclosure defined by verticalframe members 35, etc. around the fan is open except at its upperportion which is shrouded for an axial distance down from the topequivalent to about 46 percent of the axial length of the fan rotor by aconcentric cylindrical radially outspaced sheet metal shroud 45.

The downflowing air is guided into the axial entrance at the upper endof the impeller by a suitable inlet cone 46, which, in cooperationwith'shroud 45 prevents direct reentry of air from the outlet into thefan. The fan supporting shaft 50 projects upwardly above upper bearing42 where it carries a pulley 52 drivable by belt 54 which extendsoutwardly through the side of the cabinet 20 into the motor cabinet 55attached to the side of the main cabinet 20 and containing an electricmotor 56 for driving the fan. The upper end of shaft 50 and the pulley52 are closed by an internal box structure 58, and the side openingstherein through which the belt 54 extends outwardly to the motor areprotected by tubular casings which enclose the two runs of the belt 54in cooperation with a box 58 and housing 55, the casing tubes 60 beingsubstantially sealed to the openings through which the belt extends. Asbest shown in FIG. 3, the box 58 is also shaped to minimize flowrestriction.

Horizontally mounted in a lower portion of the cabinet structuredirectly above the fan entrance is a shutter assembly generallydesignated operable to close or open the inlet when desired. As alsoshown in FIGS. I and 2, the cabinet may be somewhat wider in onedimension than is needed for the air flow requirements, leaving a space68 for electrical and control components and which is compartmented fromthe remainder of the upper portion of cabinet by a partition 70 andaccessible through a removable access panel 72.

The efficiency of the fan is increased by the provision of a stationarystraightening vane plate formed of a flat piece of sheet metal extendingacross the inlet cone 46 close to the shaft and projecting downwardly asubstantial distance into the fan wheel, parallel to the axis. The plate75 stops lateral airflow through the wheel and prevents rotation of theinlet air.

In a preferred embodiment the fan has concave blade surfaces facingforwardly in'the direction of rotation, as indicated by the arrows inFIG. 2, which is quieter than the reverse rotation. The details of thefan rotor may be varied as engineering and performance requirements maydictate, but it has been found that with such a straightening vane, anda shroud band 45 which covers between 33 and 50 percent of the axiallength of the rotor, it is possible to obtain full output from a fanwheel having forwardly directed blades despite the omission of aconventional scroll housing. High fan output is thereby obtained withlow air noise.

This Detailed Description of the Preferred Embodiment of the Invention,and the accompanying drawings, have been furnished in compliance withthe statutory requirement to set forth the best mode contemplated by theinventor of carrying out the invention. The prior portions consisting ofthe Abstract of the Disclosure and the Background of thelnvention arefurnished without prejudice in an effort to comply with administrativerequirements of the Patent Office.

I claim:

I. A direct fired air heater adapted for roof installation comprising acabinet structure having a vertical air passage therethrough, roofmounting means attached to an intermediate portion of the structure forsupporting the same in an opening in a roof whereby said structureprojects both above and below the roof, characterized by air inlet meansand heating burner means in said structure and both of which are locatedabove said roof mounting means, said burner means having exposed flamedischarge means in said vertical air passage, a centrifugal fan impellermounted in said structure on a vertical axis at a position below theroofmounting means and having a 360 outlet, for drawing air downwardly fromthe air means through said vertical passage and over the exposed flamedischarge means and outwardly through said 360 outlet.

2. An air heater as defined in claim 1 wherein said impeller rotates ona vertical axis, a shaft for driving the impeller extending upwardlyfrom the impeller inside the cabinet structure to a position above themounting means, and a motor carried by and on the outside of thestructure above said mounting means for driving the shaft and impeller.

3. A direct-fired air heater adapted for roof installation comprising acabinet structure having a vertical air passage therethrough, mountingmeans attached to an intermediate portion of the structure forsupporting the same in a roof opening whereby said structure projectsboth above and below the roof, characterized by a centrifugal fanimpeller mounted in the portion of said structure which projects belowthe mounting means and having a 360 outlet, heating and air inlet meanscarried by the structure above said mounting means, the upper end of thecabinet structure being open, a caplike entrance hood overlying andextending outwardly from and downwardly in outspaced relation around thecabinet structure to define upflow air inlets, and air filter means inand accessible through said inlets.

4. A direct-fired air heater adapted for roof installation comprising acabinet structure having a vertical air passage therethrough, mountingmeans attached to an intermediate portion of the structure forsupporting the same in a roof opening whereby said structure projectsboth above and below the roof, characterized by a centrifugal fanimpeller mounted in the portion of said structure which projects belowthe mounting means and'having a 360 outlet, heating and air inlet meanscarried by the structure above said mounting means, said impeller beingmounted to rotate on a vertical axis and said portion which projectsbelow the mounting means defining a cage opening laterally in an areaperipherally around the impeller, an axial inlet to the upper end ofsaid impeller from the interior of said cabinet structure, and a baffleextending axially downwardly around the same from the cabinet structureto a position between the ends ofthc impeller.

5. An air heater as defined in claim 1 wherein said impeller rotates ona vertical axis and said portion which projects below the mounting meansdefines a cage opening laterally in an area peripherally around theimpeller, an axial inlet to the upper end of said impeller from theinterior of said cabinet structure, and a concentric annular baffleradially outspaced from and extending downwardly around the impellerfrom the cabinet structure for a distance equal to from 33 percent to 50percent of the axial length ofthe impeller.

6. An air heater as defined in claim 4 including means for rotating theimpeller in one direction, the impeller having a plurality of axiallyextending generally radial blades having concave surfaces facingforwardly in the direction of rotation.

7. An air heater as defined in claim 5 including means for rotating theimpeller in one direction, the impeller having a plurality of axiallyextending generally radial blades having concave surfaces facingforwardly in the direction of rotation.

8. In an air heater as defined in claim 7, baffle means in the inlet ofand extending axially and radially of said impeller and part way intothe same to block rotation of inlet air about the axis of the impeller.

9. In an air heater as defined in claim 6, baffle means in the inlet ofand extending axially and radially of said impeller and part way intothe same block rotation ofinlet air about the axis of the impeller.

AI-Ill UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.

Dated NOV. 24, 1970 Inventorsfi James V. Dirkes It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 3, line 11, after the word "air" insert the word -in1et--. Column4, line 36, after the word "same" insert the word -to-.

I Attest:

Edward m. mm 11-;

Officer UiCri'EEJ firm SLY-MID U1 2 19?! WW E. SQEUYLER, J Gonmissionerof Patent

